Polymers and Plastics, Chemical Engineering, Materials Science, Industrial and Manufacturing Engineering
2
Scopus Publications
Scopus Publications
Mechanical Properties, Morphology, and Viscoelastic Behavior of Polyethylene Terephthalate/Graphene Oxide Nanocomposites Brenno Lavigne Diniz, Ticiana de Oliveira Santiago, Rodrigo Santiago Coelho, Ivan Costa da Silva, Cláudia Teresa Teles Farias, Luiz Antonio Pimentel Cavalcanti Materials Research, 2025 In recent decades, much attention has been devoted to polymer nanocomposites due to their superior properties at minimal filler loadings. Among thermoplastics, polyethylene terephthalate (PET) stands out for its widespread use in the packaging industry, with research increasingly focusing on the incorporation of nanofillers such as graphene oxide (GO) to optimize its properties. The current study investigates the mechanical and viscoelastic behavior of PET/GO nanocomposites (0.02 to 0.05 wt.% GO) produced through the melt mixing technique. GO was synthesized via a modified Hummers method and transferred to a sonicated rapeseed oil dispersion prior to processing in a twin-screw extruder. Nanoindentation measurements demonstrated significant enhancements in mechanical properties with increasing GO loading, while rheological analyses revealed a notable reduction in complex viscosity. These findings confirm the dual role of GO as both a reinforcing agent and a processing aid in PET nanocomposites, achieved through a straightforward and potentially scalable processing route.
Ultrasonic and Nanoindentation Evaluation of SAF 2507 Aging: Elastic Moduli, Attenuation, and Microstructure Brenno Lavigne Diniz, Ygor Tadeu Bispo dos Santos, Virginia Ribeiro dos Santos, Ísis Morais Cruz Souza Fernandes, Ariane Cândido Batista, Luiz Antonio Pimentel Cavalcanti, Ivan Costa da Silva Materials Research, 2024 Super duplex stainless steels are highly recommended for corrosive environments. However, detrimental phases tend to precipitate in the austenite-ferrite interfaces at certain temperatures. In this study, the elastic moduli of ten specimens of SAF 2507 that underwent isothermal heat treatment at 900 ºC for different amounts of time were determined using the ultrasonic non-destructive technique. These results were validated by nanoindentation, confirming the accuracy of the ultrasonic inspection. An investigation of microstructural changes, employing optical microscopy and X-ray diffraction, enabled elucidation of how these modifications influence acoustic wave attenuation and velocity, as well as the elastic modulus. As the ferrite content decreases and the sigma phase content increases, the attenuation coefficients tend to decay, while the elastic modulus increases until a treatment time of 45 min and remains stable for higher aging times. Additionally, a robust correlation between shear wave velocity and the elastic modulus was identified.
